_ Exercise Heart Health Stress Management Stress-Free Living Why Stress & Overexertion Trigger Heart Attacks By Sondra Forsyth article Scientists believe they have an explanation for the axiom that stress, emotional shock, and overexertion may trigger heart attacks in vulnerable people. Hormones released during these events appear to cause bacterial biofilms on arterial walls to disperse, allowing plaque deposits to rupture into the bloodstream, according to research published in published in June 2014 in mBio, the online open-access journal of the American Society for Microbiology.